In the design of equipment for sorting discrete bruisable articles, particularly for sorting pieces of fruit (e.g. apples or pears) by weight, color, or other property, additional care is being taken to handle the fruit gently so as to reduce bruising. While prior art sorters, such as disclosed in U.S. Pat. Nos. 4,595,091 and 4,262,807 do not necessarily handle the fruit roughly, there is a perception in the trade that the fruit should be handled more gently and therefore manufacturers of fruit sorting equipment are attempting to respond to this perception.
The two major areas where bruising can occur in conventional article sorting equipment are in the transfer of the pieces of fruit from a singulating mechanism to the conveyance cups (which then subsequently pass over a load cell or the like), and in the discharge of the pieces of fruit at a discharge section. Often the discharge is handled so that the piece of fruit is discharged in the direction of conveyance so that it has a large velocity component in that direction. It is more desirable so as to minimize bruising to discharge the article without a significant velocity component in the direction of conveyance by moving it generally perpendicular to the direction of conveyance. While there have been a number of procedures for effecting this in the past, such as shown in U.S. Pat. Nos. 4,595,091 and 4,586,613, oftentimes a larger discharge force than desirable has been imparted to the article either due to impacting of the article with a sidewardly moving element, or because the angle of tilt necessary to discharge the article was relatively large (e.g. more than about 30.degree.).
According to the present invention, an article sorting apparatus and method are provided which seek to minimize the bruising of fruit during sorting thereof according to fruit property (particularly weight, but also possibly color, or other property thereof) while providing a simple and economical arrangement.
The apparatus according to the invention includes a continuous conveying chain elongated in a dimension of elongation with a plurality of discrete article supporting elements (cups) connected to the chain for linear movement with it, and for pivotal movement with respect to the chain about an axis generally parallel to the dimension of elongation. A plurality of stations are provided for the continuous conveying chain and article supporting elements, including a self-singulating section in which the articles are received asynchronously from a bulk supply and singulated onto the supporting elements, an article property determining section through which the articles are carried by the supporting elements without transfer and properties thereof sensed, and a discharge section in which the articles are selectively discharged at a plurality of spaced distinct locations depending upon the properties thereof sensed in the article property determining section. The self-singulating section may comprise a feed conveyor disposed at an angle with respect to the dimension of elongation and on one side of the article supporting elements, and a cushioning backstop disposed on the opposite side of the supporting elements from the feed conveyor. An overflow region before the article property determining section allows articles not singulated onto the supporting elements to move off of the supporting elements and the chain to be ultimately returned to the feed conveyor. The article property determining section preferably comprises a weighing station, having a load cell, and the elements are mounted to the chain with lost motion in the vertical direction so that they may be accurately weighed while continuously conveyed over the load cell.
The supporting elements preferably comprise plastic cups, each having a shallow depression on a top face. The depression is deep enough to positively hold the article for property determination and conveyance, but shallow enough so that the cup need be tilted only a small amount about its axis to effect discharge with minimal bruising; e.g. a generally conically shaped depression may be provided with the sidewalls thereof making an angle of between about 20.degree.-30.degree. with respect to the horizontal. Each cup includes a pin having a predetermined thickness extending outwardly from it generally perpendicular to the dimension of elongation.
The discharge section comprises a rail and a stationary cam having an upwardly angled cam surface located above the rail. The angled cam surface is vertically spaced from the rail a distance slightly greater than the thickness of the pin so as to allow passage of the pin beneath it if not deflected to the cam surface. An electromagnet or other means are provided for selectively deflecting the pin so as to engage the angled cam surface when deflected and thereby ride up the cam surface providing for discharge of the article.
The article sorter can also include a second self-singulating section, a second article property determining section, and a second discharge section following the first such sections, with the same chain and supporting elements extending therethrough. It is not believed that such an arrangement has been provided in a weight sizer before.
Apparatus according to the present invention also may comprise: A continuous conveying chain elongated in a dimension of elongation. A plurality of discrete article supporting elements connected to the chain for linear movement therewith, and including means for mounting the elements for pivotal movement with respect to the chain about an axis generally parallel to the dimension of elongation, each of the supporting elements comprising a plastic cup having means defining a shallow depression on a top face thereof, the depression being deep enough to positively hold an article for property determination and conveyance, but shallow enough so that the cup need be tilted only a small amount about the axis to effect discharge of the article. And, means for selectively effecting tilting of the cups so as to effect discharge of the articles therefrom. The cups are also mounted for lost motion in the vertical for accurate weighing, the same structure mounting the cups for pivotal movement and lost motion in the vertical.
The invention further contemplates a method of handling bruisable articles to minimize the bruising action of handling. The method comprises the steps of: (a) While continuously conveying the bruisable articles in a direction of conveyance, sequentially (a1) singulating, (a2) weighing, and (a3) selectively discharging the articles depending upon the weights thereof, utilizing a continuous mechanism so that there is no necessity for transferring the articles from one conveyance mechanism to another. And, (b) practicing said step (a3) by discharging the articles so that there is a minimal velocity component in the direction of conveyance when the article is discharged.
It is the primary object of the present invention to provide for the simple and effective sorting of discrete bruisable articles with a minimum of bruising. This and other objects of the invention will become clear from an inspection of the detailed description of the invention, and from the appended claims.